HomeWhy is it necessary to maintain a healthy aquarium? What is a physical environment?
What is a physical environment?
      The physical environment refers to aspects of an aquarium such as light, temperature, and size. Light is important for plants and fish. Fish live in a certain temperature range in the natural habitats. Space is necessary for fish to grow and mate.

Why do fish need space? 
Why do fish need optimum temperature?
Why does an aquarium need a light source